Jack doesn't notice but continues walking. "I can tell. On three we jump into the trees. One." He pauses looking back. "Two." Another pause. "Three." And he leaps into the trees on the path they are taking.
The group of five, Jack, Alec, and the three gaurds all go back towards the castle. One farther away from the vampires, Jack says "We take a different way back to make sure we aren't followed."